Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Solar Fuels , Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
Nano Lett. 2017 Mar 8;17(3):1529-1537. doi: 10.1021/acs.nanolett.6b04560. Epub 2017 Feb 9.
GaN nanowires (NWs) doped with Mg as a p-type impurity were grown on Si(111) substrates by plasma-assisted molecular beam epitaxy. In a systematic series of experiments, the amount of Mg supplied during NW growth was varied. The incorporation of Mg into the NWs was confirmed by the observation of donor-acceptor pairs and acceptor-bound excitons in low-temperature photoluminescence spectroscopy. Quantitative information about the Mg concentrations was deduced from Raman scattering by local vibrational modes related to Mg. In order to study the type and density of charge carriers present in the NWs, we employed two photoelectrochemical techniques, open-circuit potential and Mott-Schottky measurements. Both methods showed the expected transition from n-type to p-type conductivity with increasing Mg doping level, and the latter characterization technique allowed us to quantify the charge carrier concentration. Beyond the quantitative information obtained for Mg doping of GaN NWs, our systematic and comprehensive investigation demonstrates the benefit of photoelectrochemical methods for the analysis of doping in semiconductor NWs in general.
通过等离子体辅助分子束外延在 Si(111) 衬底上生长了掺镁作为 p 型杂质的 GaN 纳米线 (NWs)。在一系列系统的实验中，改变了 NW 生长过程中提供的 Mg 量。低温光致发光光谱中观察到施主-受主对和受主束缚激子，证实了 Mg 掺入 NWs。通过与 Mg 相关的局域振动模式的拉曼散射，得出了 Mg 浓度的定量信息。为了研究 NWs 中存在的电荷载流子的类型和密度，我们采用了两种光电化学技术，开路电位和 Mott-Schottky 测量。这两种方法都显示出随着 Mg 掺杂水平的增加，从 n 型到 p 型电导率的预期转变，后者的特征技术允许我们定量电荷载流子浓度。除了获得的 GaN NWs 中 Mg 掺杂的定量信息外，我们的系统和全面的研究证明了光电化学方法在分析半导体 NWs 中的掺杂方面的好处。
